Calutron receivers



Sept. 2, 1958 F. H. SCHMIDT EIAL 2,850,639

CALUI'RON RECEIVERS Filed Feb. 21, 1946 4 Sheets-Sheet V1 ATTORNEY.

F. H. SCHMIDT ET'AL 2,850,639

Sept; 2, 1958 CALUTRON RECEIVERS 4 Sheets-Sheet 2 Filed Feb. 21, 1946 INVENTOR. SCHM/DT [Pl-D H Kill/M5779 Esra/YE ATTORNEY.

FP 2, 1958 F. H. S CHMlDT EI'AL 2,850,639

CALUI'RON RECEIVERS Filed Feb. 21, I946 4 Sheets-Sheet 3 INVENTOR. [R50 H 5 CHM/01' KENNETH F STONE ATTORNEY.

Sept. 2, 1958 F.-H. scumm' ET'AL 2,350,539

CALUTRON ascmvgms Filed Feb. 21, 14e 4 Sheets-Sheet 4 W W Jill!" i I a INVENTOR. FRED H sum/0r KENNETH FSTO/VE Edi 93,539 Fatented Sept. 2, 1958 CALUTRQN nncnrvnns Fred H. Schmidt, Berkeley, Caiifi, and Kenneth F. tone, Long Branch, N. 3., assignors to the United States of America as represented by the United States Atomic Energy Sommission Application February Zl, 1946, erial No. 649,4tl0

11 Claims. ((1. ESQ-4L9) This invention involves the separation, based on difference in mass, of minute particles, such as atoms, and especially the separation of isotopes of an element, or the separation of a portion of an element enriched with respect to a particular isotope on a scale yielding commercially useful quantities of the collected material.

The type of means or mechanism to which the invention relates is known as a calutron, and correspondingly the method or process is known as a calutron method or process. In its presently preferred form, a calutron includes an evacuated chamber mounted in a magnetic field and containing apparatus for ionizing a polyisotope to be treated, apparatus for projecting one or more beams of ionized particles of the polyisotope along paths determined by the masses of the respective ions, and a target apparatus for deionizing the particles of Q the beam or beams and for retaining at least one selected isotope component thereof in a separated region from which it can be recovered.

For a complete disclosure of the essential features of a preferred form of calutron, and of its mode of operation, reference is made to United States Patent No. 2,769,222 issued May 24, 1955 to Ernest 0. Lawrence for Methods of and Apparatus for Separating Materials. The form of calutron disclosed in that patent comprises an evacuated tank placed between the poles of an electromagnet so that the evacuated space within the tank is pervaded with a substantially uniform magnetic field of high flux density. Within the tank there is provided a source unit that includes means for supplying the polyisotope as a vapor or gas to an ionizing region, ionizing apparatus for producing positively ionized particles from the vapor, and an accelerating device maintained at a high negative electrical potential with respect to the ionizing apparatus for withdrawing the positive ions and imparting to each of them a predetermined energy in the form of substantially uniform velocities along paths generally normal to the direction of the magnetic field toward a beam defining slit in the accelerating device disposed generally parallel to the direction of the magnetic field.

The accelerated ions move transversely to the magnetic field and are constrained to travel along arcuate paths having radii that vary with the masses of the particles. By virtue of the accelerating slit construction, the paths for the ions of a given mass diverge from a median path to an extent determined by the geometry of the ionizing and accelerating devices. This divergence of the paths of travel of the ions of a given mass continues through the first 90 of arcuate travel, and then the paths converge during the next 90 and cross each other in a region of focus approximately 180 from the source unit. Thus, in effect, geometrical focusing of a ribbon-shaped stream of ions of a given mass is accomplished adjacent the 180 point, even though there is a relatively wide angle of divergence of the ions at their source.

Similarly, the ions of any other given travel 2 along paths that define a ribbon-shaped stream coming to a focus having a rectangular pattern at approximately 180 from the accelerating apparatus. Being composed of ions of different masses, the streams of ions of dilierent isotopes have radii of curvature that differ by an amount dependent solely upon the mass difference of their respective constituent ions. As a result, corresponding points within the foci of the streams of different isotopes are spaced apart by an amount approximately equal to the ditference in the diameters of the respective paths of the constituent ions. In the case of the heavier elements, such as uranium, the difference in mass between the isotopes is not suflicient for accomplishing complete separation of the streams in which the ions of the difierent isotopes respectively travel, while employing a practical minimum divergence of the beam at the beam defining slit, and a plurality of overlapping streams having overlapping feel are created.

A receiver is disposed within the vacuum tank adjacent the 180 foci of the isotope ions to be separated, for deionizing them and for separately collecting one or all of them as may be desired. Because of the necessary overlapping of the streams at their foci, it is impractical in one operation to separate completely the isotopes of the heavier elements, and, in practice, the separated quantities of material collected at the receiver are merely enriched with respect to a particular isotope. Y

In another United States patent to Ernest 0. Lawrence, No. 2,714,644, issued August 2, 1955, for Calutrons, a number of forms of a calutron are disclosed in which a plurality of ion beams are transmitted in the evacuated space within a single tank. Several of these forms (Figures 15, 16 and 30) involve a source unit for transmitting a plurality of ion beams in noninterfering, intersecting relation through the interior of the evacuated tank to respective, closely adjacent regions of focus and a single receiver disposed in the paths of the plurality of beams at their regions of focus for collecting desired material therefrom.

The present invention relates to that part of a calutron referred to as the receiver, and the illustrated embodiment is designed particularly to receive a plurality of non-interfering, intersecting, uranium ion beams, of the general type disclosed in the last-mentioned Lawrence patent, for separating a portion of each beam enriched with respect to the U isotope. Throughout the following description, the U isotope will be ignored, as it comprises too small a proportion of normal uranium to be of any importance as a contaminant of the product separated by the particular receiver illustrated.

An object of the invention is to provide a calutron receiver adapted separately to collect and retain a maximum percentage of the ions traveling in a selected portion of each of a plurality of closely adjacent ion beams.

Another object of the invention is to provide a calutron receiver having a plurality of ion receiving pockets for respectively collecting and retaining a maximum percentage of the ions traveling in a selected portion of each of a corresponding plurality of closely adjacent ion beams.

Another object of the invention is to provide an improved unitary calutron receiver for a plurality of closely adjacent ion beams.

Another object of the invention is to provide a calutron receiver having a plurality of ion receiving pockets for respectively collecting and retaining the maximum percentage of the ions traveling in a selected portion of each of a corresponding plurality of closely adjacent ion beams, the pockets being contained in a single housing adapted to be mounted as a unit in a calutron tank.

Another object of the invention is to provide a unitary calutron receiver adapted to be disposed in a calutron tank at the 180 regions of focus of a plurality of closely V p 3 adjacent, non-interfering, intersecting ion beams with a face plate of the receiver disposed in the paths of the beams, the face plate being provided with a correspondingplurality of apertures for respectively passing selected delimited'portions or" the beams to respectively associated ion receiving pockets contained in a unitary housing.

Another object of the invention is to provide a calutron receiver having' an ion receiving'pocket for separately collecting and retaining ions traveling in a selected portion'of one isotope component of an ion beam and an electrode for intercepting ions traveling in a corresponding contiguous portion of' another isotope component of the ion beam.

Another object of the invention is toprovide a'calutron receiver having an ion receiving pocket for separately collecting and retaining ions traveling in a selected por tion of an ion beam and an electrode for intercepting ions traveling in another selected portion of the ion beam, the electrode. being disposed so as to delimit one side of the portion of the ion beam admitted into' the ion receiving pocket.

Still further objects of the invention will appear from 'the following description of a preferred embodiment thereof and from the accompanying drawings, in which: 7 Fig. 1 is a horizontal, sectional view of a calutron tank, showing the arrangement of a double source unit, or

'pair of source units, and a double receiver within the tank and the relation of the tank to the magnet, certain parts being shown somewhat schematically for simplicity;

7 section being indicated by the line; 4-4 in Fig. '3; and

,Fig. 5 is an elevational view. of the receiver, looking toward the beam viewing face thereof, with one of a pair of doors for one beam in a closed positionand the other of. the'pair of doors removed to show more clearly the: posterior structure of the beam viewing. face.

Referring to the drawings, Fig. 1 illustratesv a calutron.

of the general character disclosed-in the Lawrence -Patent No.2,709,222, mentioned above, but embodying cer- .tain' modifications including,,among, other features, ap-

paratus for transmitting a pair of ion beams. innoninterfering, intersecting relationthrough the'interior of an evacuated tankrto respective, closely adjacent regions ofregion of focus at angles with respect to a median path. (path of 0 divergence) equal to their respective initial angular divergences. Streams of ions of different mass transmitted as a single beam by 'such a source unit follow similar paths except that the paths of the ions of greater mass have a somewhat greater radius of curvature, so that the median paths of two streams of ions of different mass transmitted from a single source unit arrive at spaced-apart 180 regions of focus.

In Fig. 1, the 'two beams transmitted 'by the source units 13 are schematically and somewhat ideally illustrated by two sets of two lines each. One set represents a median path 15 and another median path 16 for streams of ions of the U and .U isotopes, respectively, that are transmitted'from one of the pair of source units; and the other set represents a median path 17 and another median path 18 for streams of ions of the U and U isotopes, respectively, that are transmitted from'the other of the pair of source units. The two streams of ions represented. by the median paths 15 and 16 from one source unit pass through respective 180 regions of focus 19 and 20, and the two streams by the median paths 17 and 18, in a region 23 without interfer ence, as disclosed in the second mentioned Lawrence Patent No. 2,714,644. A single source 'unit capable of producing an ion beam such as those described herein 7 is disclosed in detail in the first mentione'dlawrence Patent No. 2,709,222.

A receiver, generally designated 25, is mounted on a removable .end wall. 14 of the C-shaped tank 10, at the opposite end thereof from the source units 13, for collecting and deioni'zing ions arriving. at the U region of" focus 19 separately from those'arrivingatthe adjacent U region of focus 20 and for collectin'g'and deionizing' ions arriving at the other U region of focus 21 separately from those arriving at the adjacent Um-region of focus 22, and for trapping :ions 'reachingrthe U -regions of focus 19 and 21 in different regions within thereceiver V in such a manner that. they can. be removed from the calutron separately from the ions arriving at the U 3 regions of focus 20 and 22.

The receiver 25 is mounted on a tube26'that projects outwardly through an aperture. (not shown) .in the. adja centend wall Mofthetank 10,.the tube 26 being mounted on the adjacent end wall 14 and insulated therefrom in focus and a unitaryreceiver disposed. 'in, the paths of both ion beams at their regions of focus for collecting desired material therefrom. The calutron comprises a C-shaped tank 10 supported midway between, a pair of' horizontally disposed, vertically spaced-apartpole faces 11 (only one being shown) of .a calutron magnet, whereby a substantially uniform magnetic .field may be created throughout the interior of the tank with the flux 'paths passing upwardly 'therethrough. The-tank 10 is adapted. to be evacuated through a pump-out conduit 12 -to re; duce the interior-pressure, in a manner disclosed in'the; above-mentioned Lawrence Patent .No. 2,709,222.

A pair of identical source units both designated 13 topiecharge' material, apair of beams of singlyionized positive ions traveling along.similar intersecting, arcuate paths to respective regions of focus approximately along said pathstoward the .oppositeendof the tank As hereinbefore indicated, eachsource unit 13I-may' be.

designed toproject ions :of a given .mass alongpaths', that are initially divergent to either. side. of. amedian path by various angles between predeterminedmaxima and that later converge toward and diverge beyond a:

any desired manner, as by acylindrical insulator support 27 secured to the end wall and surrounding the tubular support 26. V V

The receiver 25 comprises aback plate 30 of rectanguular configuration havingacentrally disposed aperture. 31 therein. The inner end of the supporting tube 26 is secured in the aperture 31 for ready removal by -rneans of a flange 32 that may be soldered to the tube, and a cooperating series of fastening. elements-33 that pass through the flange 32 and into the back plate 30.

The back plate 30 forms part of a housing that projects.

forwardly from the. backplate and includesa pair-of oppositely disposed side plates 34 and a pair'of oppositely disposed end plates 35, the side plates-34. and end-plates '35 being mounted onth e back plate 30 and secured thereto by fastening elements 36. The end .plates and .side.

plates may be secured together along their iadjoining edges in any desired'manner, as by soldering.

The entireinterior structure. of the receiver and of V the face plate therefor and associated parts, presentlyf to be described; are mounted on' four pairs of standoff insulators, two pairs of insulators 39'being respectively secured in any suitable manner in spaced apart relation along one sideof the back plate and theother two pairs.

of insulators 40 being similarly disposed on the opposite side of the'back plate. a One. pair of.-insulators.39, lo-' cated adjacent the bottom of the back plate, supports a metal plate 41; and the other pair of insulators 39, located adjacent the top of the back plate, supports an identical metal plate. Similarly, a lower pair of the insulators 40 supports a metal plate 42, and the other pair of insulators 46 supports another identical plate 42. Two pairs of tubular members 43 and 44 are respectively soldered to and project forwardly from the four plates supported by the insulators 3g and 40 and provide a relatively rigid supporting structure to which a metal face plate 45 may readily be secured, the insulators 39 and 40 serving to insulate the face plate from the receiver housing.

The face plate 45 is provided with a large, centrally disposed, rectangular opening 46 therethrough, the opening being large enough to pass the entire U and U portions of both beams, except for scattered material arriving entirely outside the normal regions of focus for the two beams. To prevent warping of the face plate 45, a pair of angle members 47 are respectively soldered along opposite ends of the face plate.

A beam defining structure comprising a generally rectangular graphite plate having a pair of elongated rectangular openings therein, and a pair of graphite U electrodes 51 and 52 respectively disposed within the rectangular openings of the graphite plate 50, is mounted in alignment with the aperture 46 in the face plate 45 with the forward surface of the graphite plate 59 abutting the rearward surface of the face plate 45 around the entire perimeter of the aperture 46 therein. A pair of metal bars 53 respectively extend adjacent the side edges of the graphite plate 50 along the back side thereof, and fastening elements 54 pass through the face plate and through the graphite plate into the bars 53 to hold the graphite plate in place and to reinforce it against warping. Another pair of metal bars 5'5 respectively extend adjacent the end edges of the graphite plate along the back side thereof and are fastened in place similarly to the metal bars 53 by fastening elements 56 to provide additional support for the graphite plate 50.

One of the U electrodes 51 in one of the elongated rectangular openings of the graphite plate 5%) extends the length of this opening and about one half the width thereof and is mounted therein, in a manner described hereinafter, so as to define one side of a U slot 69 for passing a predetermined cross sectional area of the U portion of one of the beams; and the other U electrode 52 is similarly disposed in the other elongated rectangular opening of the graphite plate 5% and defines one side of a second U slot 61 for passing a predetermined cross sectional area of the U portion of the other beam. On the opposite side of the U electrode 51 from the adjacent U slot, the electrode is spaced slightly from the adjacent edge of the surrounding opening in the graphite plate 56; and an elongated graphite baffle member 62 is secured to the graphite plate so by fastening elements 63 and extends partially behind this U electrode 51 along its entire length so as to intercept ions passing through the small space between the electrode and the adjacent edge of the surrounding opening in the graphite plate 50. The other U electrode 52 is similarly disposed in the other opening of the graphite plate 50, and a second graphite bafile member 64 is secured to the graphite plate 59 by fastening elements 65 and extends behind this U electrode along its entire length for intercepting ions passing between this electrode and the adjacent edge of the surrounding opening in the graphite plate 56.

With this arrangement of the U electrodes and respectively associated U slots in the beam viewing face of the receiver, each electrode actually defines one side of the U portion of the beam passed by the adjacent U slots, and the necessity for employing an intermediate beam defining strip is eliminated, thus permitting the use of Wider slots and the collection of a larger portion of the beam. Moreover, the ion intercepting face of each electrode may be of a size and shape and may be so disposed that it intercepts a segment of the U portion of the beam corresponding exactly to the U portion of the beam passed by the adjacent U slot. Thus, knowing the ratio of U ions to U ions in the beams to be received, the quantity of ions entering the U slots may be obtained simply by multiplying the U current readings by this ratio.

In order to prevent the passage of ions through the two U slots 6% and 61 during the warmup period, before the beams have become stabilized and have been focused for reception, a pair of doors 66 and 67 are respectively mounted in front of the face plate 45 on two pairs of hinges 68 and 69. Each door is slightly greater in length than the U slot to be opened and closed thereby and is adapted to swing about its hinges from a closed position against the face plate and covering the two U slots (as shown in Fig. 3) to an open position out of the paths of the U+ portions of the beam (as shown in Fig. 1).

For operating the doors 66 and 67 between their open and closed positions, two substantially identical mechanisms are respectively associated therewith. Referring either to the door 66 or the door 67 and its associated operating mechanism, a rod 70 is pivotally connected to the door by means of a bracket 71 and projects into the interior of the receiver through an aperture 72 in the face plate 45. One end of a length of heavy wire 73, such as music wire, is mounted in an aperture 74 that extends axially into the rearward end of the rod 70, and a set screw 75 carried by a collar 76 projects into a transverse aperture 77 in the rod 76 and against the wire 73 to anchor it in place. The Wire 73 extends generally rearwardly from the rod 76 into the receiver supporting tube 26, where it is connected to a suitable pushpull type of control for moving it and the associated rod 76 longitudinally to open and close the associated door.

A tubular sleeve 7S surrounds the wire 73 along most of its length and is anchored at both ends against longitudinal movement. Within the receiver housing, the sleeve 78 may be secured against longitudinal movement by means of any suitable bracing structure 79, that may be soldered or otherwise fastened to one end of the sleeve and to the adjacent pair of tubular members 43 or 44. The sleeve is bent to conform to a desired path of travel for the wire 73, whereby electrical contact between it and other parts of the receiver may be avoided. A suitable push-pull control for the wire 73 and anchor for the rearward end of the sleeve 78 are disclosed in United States Patent No. 2,745,965 to Edward I. Lofgren, which issued May 17, 1956.

To facilitate determining when the beams are properly focused for most efficient reception, a pair of narrow slots 8% and 31 are respectively provided in the doors 66 and 67, the slots being so disposed in the associated doors that they are respectively aligned with the longitudinal center lines of the two U electrodes 51 and 52 when the doors are in their closed positions. Though the lengths of the slots 30 and 81 are not of critical importance, it is preferred that they extend only a short distance parallel to the longitudinal center lines of the respectively aligned U electrodes and that they be centrally disposed with respect to the midpoints of these longitudinal center lines. The widths of the slots 86 and 81 are likewise not of critical importance, as disclosed in the above-mentioned Lofgren patent, but are preferably only a fraction of the widths of the respectively aligned U electrodes.

Thus, with the doors 66 and 67 in their closed positions, a segment of greatest ion intensity of the U portion of each of the two beams Will pass through the associated slot 8i or 31 to the aligned U electrode 51 or 52 when the U portion of the beam is properly focused upon its For each beam, the spacing betiveenthe longitudinal center line of the associated U electrode "and the longitudinal center line, of V the. contiguous U slot is cho sen'equal to the spacing bea tween the lines of maximum U and U ion intensity in the beam. With this arrangement, focusing of the beams so that the maximum quantities of ions pass through the door slots 80 and '81 to the respectively aligned electrodes 51 and 52 'serves to center theU foci of the beams on their respective U slots 60 and 61 After the beams are properly focused, thedoors 7 may be opened to permit reception.

A pair of identical ion receiving pockets, generally designated and 86, are disposed inside the receiver housing behind the tw o U Jslots and 61 respectively 7 interior dimensions of this enclosure 'so that the exterior surface of the liner will be in contact with substantially the entire area of the interior surfaces of the enclosing plates. The liner 92 is provided with an opening 93, slightly larger in each dimension than the U slot with which it 'is to be associated, for admitting into the interior of the liner ions passing through the associated slot; and a baflle 94; that extends the'full length of the pocket liner-r92, is secured thereto adjacent one side of the opening {)3 and projects inwardly a substantial distance in a -direction generally parallel to the paths of travel of ions entering the pocket in order to assist in trapping ions that might otherwise rebound out through the'opening 93.

In order .to provide a suitable mounting for thetwo pockets and 86, a pair of bars and 101 are disposed in spaced apart parallel relation} and are secured at their opposite ends to the plates Hand 42 in any suitable manner, as by welding. Referring to the pocket 85, a pair of tubular insulators 102 and 103 and a plate.

154 are disposed between'the supporting bar 101 and the 7 adjacent end of the 'rear wall 91 of the pocket, the plate 194 being provided with a pair of grooves 105 conforming to the cylindrical contour of the tubular: insulators 102 and 103 to provide seats therefor. in Fig. 4, the plate 104 issecured-to the bar 101 by a' fastening element'106 that passes through the bar and is threaded into thepln'te; and-the insulators102 and 103 are clampedbetween-the plate 104- and the rear wall 91 of the pocket by a pair of studs 107 that are soldered at one end route rear 'Wall of the pocket and project between the two insulators and through the plate 104, from which they-ere electrically insulated by; ceramic sleeves 108 'and 109.- --'Each stud 107 is provided with a nut and Washer combination 110 that bears against-the associated insulating sleeve 109 to-clar'np firmly together the asseme bly comprising the plate 104, the tubular insulators 102 and 103, and the rear wall 91 of the pocket] An identical 'support is provided between the opposite endvof the rear wallof the pocket 85 and the bar 100, and'a pair of identical supports are provided between opposite endsof"the';pocl et as and'the'bars 10c" and 101; With this arrangement, a rigid mounting'f oreach pocket is provided while maintaining the pocket butofelectrical contact with the receiverho'using, r i i .The'two"U electrodes 51 and 52 are identicallymounted on the side plates 83 of the respectively associated'pockets185 andj86 in insulated relation thereto. The structure supporting each 'U electrode comprises a bracket 112 securedat'its forward end to the electrode'b'y a number inf-fastening elements 113 and adjacent its rearward and to a plate 114 by a number of fastening elements 115. The plate 114 islsecured adjacent its opposite As best shownpocket side Wall 88 and the plate 114, and the-assembly is clamped together a pair of nuts'fid and a of 1 ceramic insulatorWashers-119 on the projecting ends of 1 With this arrangement, the plates 114 and associated electrodes'51 and 52' are maintained out of elec; trical contact with the side Walls 88'of the pockets to which they are respectively secured.

For cooling the face plate 45, 1: csp erjtuee cooling line 12 5 is led into the receiver housing through the porting tube 26, and thence partially around the inter of? structure contained Within the housing and forwa'rdly into I contact with the face plate 45 adjacent'one corner" thereof.

The portion of the cooling fluid line 120 in contact with the face plate 45 extends substantially the full length:

of adjacent one'side edge, thence around the interior shun ture contained within the receiver housing to 'a-point'on the opposite side of the face plate adjacent its upper en and finally downwardly the full length thereof, after which the line is led partially around the interior struc{' ture contained within the receiver housingand out the receiver again through the supporting tube 26; neat conducting relation between the cooling fluid line 120 and face plate islpreferably maintained throughout the por on of the line in contact with'the face pl-ate'hy soldering that portion of the line directly thereto.

The cooling fluid line 120 is maintained out ofelectrical contact with all parts of the receiverexcept theraee plate with which it is associated and is mounted \tlithi'ii'thft supporting tube 26 by mean'sof an insulating disk a manner disclosed and described in some detaillin the above-mentioned Lofgren patent. With this arrangement, and by employing anelectrically nonconducting cooling fluid, the cooling fluid line 120 may be employed as an electrical lead for reading currents to the face plate 45.

For cooling the two. U electrodes 51 andt52, a'pair of independent cooling fluid lines 124 and 125' areerrr-j ployed. Referring to the cooling fluid line 125'f0i' the" electrode 52, the cooling fluid supply is' brought into the'. receiver through a conduit formed between a pair; of concentric copper tubes 126 and 127 that are led meme 7 receiver housing through the supporting tube 26fi1d through the insulating disk 121 to a fitting 128 dispese i within the receiver housing adjacent the opening531 the back plate 30. The passageway'between the tw centric tubes 126 and 127 is connected with one end of the cooling fluid line 125 through the fitting 128; and the opposite end of the cooling fluid line 125 is conneifteli through the fitting with an interior passageway defined by theinner one of the concentric tubes 127 in order topro" vide a return line for the cooling fluid for conductihg it back'out of the receiver. J

The two ends of the cooling fluid line 124VfoitlfeiU V electrode 51 are respectively connected with theftwdfpassages formed vby a second pair of concentric 'tu'bfes" 1 29" and 130, througha second fitting (not shown) dismay be identical with the fitting-128 associated with the? abovedescribed cooling fluid line 125. The two 'cooling jfluid lines 124 and 125 respectively form cooling fluid circuits in heat conducting relation with the two electrode supporting plates 114, each of these cooling fluid line's being partially supported against its associated electrode sup, porting plate by means 'of'an elongated block'131E'and fastening elements'1'32. Toobtain an adequateflow of.

7'51 electrical contact with all parts of the receiver except the 9 plates 114 to which they are respectively connected. With this arrangement, and by employing a nonconducting cooling fluid, the cooling fluid lines 124'and 125 may respectively be employed as electrical leads for reading currents to the U electrodes 51 and 52.

With the receiver 25 mounted in the evacuated tank 10, with cooling fluid circulating through the cooling fluid lines 124 and 125, and with the doors 66 and 67 in their closed positions, the two beams may be created and focused in accordance with the indicator currents to the U electrodes 51 and 52. When both beams have been properly focused, the doors 66 and 67 are opened, and subsequent readings of current to the electrodes 51 and 52 may be observed as a check on general beam conditions and on the rate at which ions are entering the pockets 85 and 86.

Either or both of the doors 66 and 67 may be closed during a run in the event the condition of one or both of the beams should become unfavorable, in order to prevent contamination of'the material in the pockets S and 86 until the condition of the beam or beams is corrected; or the doors may be closed at regular intervals during a run to obtain a more reliable check on the accuracy of focus of the beams and to carry out any required refocusing operations.

At the conclusion of a run, the beams are cut off, the circulation of cooling fluid through the receiver is stopped, the pressure in the tank is brought up to atmospheric pressure, and the receiver is removed from the tank by remov ing the tank end wall 14 on which it is mounted. After removing one of the end plates 35 of the receiver housing, and one of the end Walls 89 of each of the pockets 85 and 86, the two pocket liners 92 may be withdrawn for recovering the material collected therein during the run.

While we have described in detail a specific embodiment of our invention, it is to be understood that this has been done for illustrative purposes and that the scope of our invention is not limited thereby except as required by the appended claims.

What is claimed is:

1. In a calutron including a tank and means for transmitting a plurality of ion beams within the tank, a receiver for said beams comprising a frame structure having an apertured viewing face presented to said beams for passing selected portions thereof, and a plurality of pockets mounted on said frame structure in cooperative relation with apertures in said face plate for receiving ions passing through said apertures.

2. In a calutron having means for establishing a plurality of ion beams and for causing divergence of beam components of different mass within each beam during travel of said components to a region of focus, a unitary ion receiver comprising a pair of collecting pockets respectively associated with said beams, each pocket having an opening therein disposed adjacent the region of focus of the associated beam for admitting a selected delimited portion thereof.

3. In a calutron having means for establishing a plurality of ion beams and for causing divergence of beam components of different mass within each beam during travel of said components to a region of focus, a receiver comprising a housing containing a pair of collecting pockets respectively associated with said beams, each of said pockets having an opening therein disposed adjacent the region of focus of the associated beam for admitting a selected delimited portion thereof.

4. In a calutron having means for establishing a plurality of ion beams and for causing divergence of beam components of different mass Within each beam during travel of said components to a region of focus, a receiver comprising a housing, a face plate mounted on said housing in the paths of said beams adjacent the regions of' focus thereof, a pair of apertures in said face plate for respectively passing selected delimited portions of said beams, and a pair of collecting pockets mounted within said housing and respectively aligned with said apertures, each of said pockets having an opening for admitting to the pocket ions passing through the aligned aperture in the face plate.

5. In a calutron having means for transmitting an ion beam, an ion receiver comprising means for passing a selected delimited portion of the beam to an ion receiving pocket, said means including an electrode for delimiting one side of the portion of the beam passed to the ion receiving pocket.

6. In a calutron having means for transmitting an 'ion beam, an ion receiver comprising an ion receiving pocket for separately collecting ions travelling in a selected portion of the ion beam, and an electrode for intercepting ions travelling in a selected contiguous portion of the ion-beam.

7. In a calutron having means for transmitting an ion beam, an ion receiver comprising an ion receiving pocket for separately collecting ions travelling in a selected portion of the ion beam, and an electrode for intercepting ions travelling in a selected contiguous portion of the ion beam, the electrode being disposed so as to delimit one side of the portion of the ion beam admitted into the ion receiving pocket.

8. in a calutron having means for transmitting an ion beam and for causing divergence of beam components of different mass during travel .of said components to respective regions of focus, an ion receiver disposed adjacent said regions of focus and comprising an ion receiving pocket having an opening therein for admitting a selected delimited portion of the ion beam, means disposed in the path of said beam for delimiting one side of the portion thereof admitted through the opening of the pocket, and an electrode disposed in the path of said beam for delimiting another side of the portion thereof admitted through the opening of the pocket.

9. In a calutron having means for transmitting an ion beam and for causing divergence of beam components of different mass during travel of said components to respective regions of focus, an ion receiver comprising a viewing face disposed in the path of the ion beam adjacent said regions of focus and having an aperture therein for passing a selected delimited portion of the beam to an ion receiving pocket, and an electrode disposed within said aperture for delimiting one side of the portion of the beam passed to the ion receiving pocket.

10. In a calutron having means for transmitting an ion beam and for causing divergence of beam components of different mass during travel of said components to respective regions of focus, an ion receiver comprising a viewing face disposed in the path of the beam at said regions of focus and having an aperture therein for passing a delimited portion of the beam, an electrode disposed within said aperture for delimiting one side of the portion of the beam passed thereby, and an ion receiving pocket aligned with the aperture in said viewing face for receiving the delimited portion of the beam passed thereby.

11. In a calutron having means for transmitting an ion beam and for causing divergence of beam components of different mass during travel of said components to respective regions of focus, an ion receiver comprising a viewing face disposed in the path of the beam at said regions of focus and having an aperture therein for passing a delimited portion of the beam, an electrode disposed within said aperture for delimiting one side of the portion of the beam passed thereby, and an ion feceivin'g, pocket-having an openifig'therein aligned with 2,200,095 the aperture in said viewing face for receiving the, 7 2,354,122. delimited .poi'tion of the'f-iieam. passed thereby. 2,412,359

References Cited in the file of this patent 5 UNITED STATES PATENTS 2,086,546 Gear e July '13, 71937 

